Devices and methods of vertebral disc augmentation

ABSTRACT

A disk herniation constraining device for implantation into a vertebral disk can include a support member for support of a herniated portion of a disk. The support member can be connected to an anchor. The constraining device can include the insertion of augmentation material within the disk. A defect in the annulus of a disk can be closed using a prosthesis such as a barrier. 
     The barrier can be placed between the annulus and the nucleus of the disk. The barrier can include a sealant and an enlarger. The barrier can be implanted into the disk using a delivery cannule, an advancer and at least one control filament to control the positioning of the barrier over the defect. A stiffening element can be included within the barrier to impart stiffness to the barrier.

RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.60/149,490 filed Aug. 18, 1999, U.S. Provisional Application No.60/161,085 filed Oct. 25, 1999 and U.S. Provisional Application No.60/172,996 filed Dec. 21, 1999, the entire teachings of theseapplications being incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to the surgical treatment ofintervertebral (IV) discs in the lumbar, cervical, or thoracic spinethat have suffered from tears in the annulus fibrosus, herniation of thenucleus pulposus or significant disc height loss.

The disc performs the important role of absorbing mechanical loads whileallowing for constrained flexibility of the spine. The disc is composedof a soft, central nucleus pulposus (NP) surrounded by a tough, wovenannulus (AF). Herniation is a result of a weakening in the AF.Symptomatic herniations occur when weakness in the AF allows the NP tobulge or leak posteriorly toward the spinal cord and major nerve roots.The most common resulting symptoms are pain radiating along a compressednerve and low back pain, both of which can be crippling for the patient.The significance of this problem is increased by the low average age ofdiagnosis, with over 80% of patients in the U.S. being under 59.

Since its original description by Mixter & Barr in 1934, discectomy hasbeen the most common surgical procedure for treating IV disc herniation.This procedure involves removal of disc materials impinging on the nerveroots or spinal cord posterior to the disc. Depending on the surgeon'spreference, varying amounts of NP is then removed from within the discspace either through the herniation site or through an incision in theAF. This removal of extra NP is commonly done to minimize the risk ofrecurrent herniation.

Nevertheless, the most significant drawbacks of discectomy arerecurrence of herniation, recurrence of radicular symptoms, andincreasing low back pain. Re-herniation can occur in up to 21% of cases.The site for re-herniation is most commonly the same level and side asthe previous herniation and can occur through the same weakened site inthe AF. Persistence or recurrence of radicular symptoms happens in manypatients and when not related to re-herniation, tends to be linked tostenosis of the neural foramina caused by a loss in height of theoperated disc. Debilitating low back pain occurs in roughly 14% ofpatients. All of these failings are most directly related to the loss ofNP material and AF competence that results from herniation and surgery.

Loss of NP material deflates the disc, causing a decrease in discheight. Significant decreases in disc height have been noted in up to98% of operated patients. Loss of disc height increases loading on thefacet joints. This can result in deterioration of facet cartilage andultimately osteoarthritis and pain in this joint. As the joint spacedecreases the neural foramina formed by the inferior and superiorvertebral pedicles also close down. This leads to canal stenosis,pinching of the traversing nerve root, and recurring radicular pain.Loss of NP also increases loading on the remaining AF, an innervatedstructure that can produce pain. Finally, loss of NP results in greaterbulging of the AF under load. This can result in renewed impingement bythe AF on nerve structures posterior to the disc.

Persisting tears in the AF that result either from herniation orsurgical incision also contribute to poor results from discectomy. TheAF has been shown to have limited healing capacity with the greatesthealing occurring in its outer borders. Healing takes the form of a thinfibrous film that does not approach the strength of the uninjured disc.Surgical incision in the AF has been shown to produce immediate and longlasting decreases in stiffness of the AF particularly against torsionalloads. This may over-stress the facets and contribute to theirdeterioration. Further, in as many as 30% of cases, the AF never closes.In these cases, not only is re-herniation a risk but also leakage offluids from within the NP into the epidural space can occur. This hasbeen shown to cause localized pain, irritation of spinal nerve roots,decreases in nerve conduction velocity, and may contribute to theformation of post-surgical scar tissue in the epidural space.

Other orthopedic procedures involving removal of soft tissue from ajoint to relieve pain have resulted in significant, long lastingconsequences. Removal of all or part of the menisci of the knee is oneexample. Partial and total meniscectomy leads to increasedosteoarthritic degeneration in the knee and the need for further surgeryin many patients. A major effort among surgeons to repair rather thanresect torn menisci has resulted in more durable results and lessenedjoint deterioration.

Systems and methods for repairing tears in soft tissues are known in theart. One such system relates to the repair of the menisci of the kneeand is limited to a barbed tissue anchor, an attached length of suture,and a suture-retaining member, which can be affixed to the suture andused to draw the sides of a tear into apposition. The drawback of thismethod is that it is limited to the repair of a tear in soft tissue. Inthe IV disc, closure of a tear in the AF does not necessarily preventfurther bulging of that disc segment toward the posterior neuralelements. Further, there is often no apparent tear in the AF whenherniation occurs. Herniation can be a result of a general weakening inthe structure of the AF (soft disc) that allows it to bulge posteriorlywithout a rupture. When tears do occur, they are often radial.

Another device known in the art is intended for repair of a tear in apreviously contiguous soft tissue. Dart anchors are placed across thetear in a direction generally perpendicular to the plane of the tear.Sutures leading from each of at least two anchors are then tied togethersuch that the opposing sides of the tear are brought together. However,all of the limitations pertaining to repair of IV disks, as describedabove, pertain to this device.

Also known in the art is an apparatus and method of using tension toinduce growth of soft tissue. The known embodiments and methods arelimited in their application to hernias of the IV disc in that theyrequire a spring to apply tension. Aside from the difficulty of placinga spring within the limited space of the IV disc, a spring will induce acontinuous displacement of the attached tissues that could bedeleterious to the structure and function of the disc. A spring mayfurther allow a posterior bulge in the disc to progress should forceswithin the disc exceed the tension force applied by the spring. Further,the known apparatus is designed to be removed once the desired tissuegrowth has been achieved. This has the drawback of requiring a secondprocedure.

There are numerous ways of augmenting the IV disc disclosed in the art.In reviewing the art, two general approaches are apparent—implants thatare fixed to surrounding tissues and those that are not fixed, relyinginstead on the AF to keep them in place.

The first type of augmenting of the IV disk includes generally replacingthe entire disk. This augmentation is limited in many ways. First, byreplacing the entire disc, they generally must endure all of the loadsthat are transferred through that disc space. Many degenerated discs aresubject to pathologic loads that exceed those in normal discs. Hence,the designs must be extremely robust and yet flexible. None of theseaugmentation devices has yet been able to achieve both qualities.Further, devices that replace the entire disc must be implanted usingrelatively invasive procedures, normally from an anterior approach. Theymay also require the removal of considerable amounts of healthy discmaterial including the anterior AF. Further, the disclosed devices mustaccount for the contour of the neighboring vertebral bodies to whichthey are attached. Because each patient and each vertebra is different,these types of implants must be available in many sizes.

The second type of augmentation involves an implant that is not directlyfixed to surrounding tissues. These augmentation devices rely on an AFthat is primarily intact to hold them in place. The known implants aregenerally inserted through a hole in the AF and either expand, areinflated, or deploy expanding elements so as to be larger than the holethrough which they are inserted. The limitation of these concepts isthat the AF is often not intact in cases requiring augmentation of thedisc. There are either rents in the AF or structural weaknesses thatallow herniation or migration of the disclosed implants. In the case ofa disc herniation, there are definite weaknesses in the AF that allowedthe herniation to occur. Augmenting the NP with any of the knownaugmentation devices without supporting the AF or implant risksre-herniation of the augmenting materials. Further, those devices withdeployable elements risk injuring the vertebral endplates or the AF.This may help, but again herniations do not require a rent in the AF.Structural weakness in or delamination of the multiple layers of the AFcan allow these implants to bulge toward the posterior neural elements.Additionally, as the disc continues to degenerate, rents in theposterior annulus may occur in regions other than the original operatedsite. A further limitation of these concepts is that they require theremoval of much or all of the NP to allow insertion of the implant. Thisrequires time and skill to achieve and may permanently alter thephysiology of the disc.

The known art relating to the closure of body defects such as herniasthrough the abdominal wall involve devices such as planer patchesapplied to the interior of the abdominal wall or plugs that are placeddirectly into the defect. Each describes a planar patch. Such devicesare limited in their application in the intervertebral disc for severalreasons such as by the disc's geometry. The interior aspect of the AF iscurved in multiple planes, making a flat patch incongruous to thesurface against which it must seal. These devices are further limited bythe instruments or stiffening elements incorporated into the peripheryof the patch. The disc height is rarely greater than 5 mm. With aperipherally supported patch, two segments of such elements would spanany given location along the patched surface. This requires that eachstiffening element have a thickness along the height of the disc of lessthan 2.5 mm, making them considerably weaker than the central enlargingmeans disclosed in this invention. Finally, the prior art disclosespatches that are placed into a cavity that is either distended by gas orsupported such that the interior wall of the defect is held away frominternal organs. In the disc, it is difficult to create such a cavitybetween the inner wall of the annulus and the NP without removingnucleus material. Such removal may be detrimental to the clinicaloutcome of disc repair.

One hernia repair device known in the art is an exemplary plug. Thisplug may be adequate for treating inguinal hernias, due to the lowpressure difference across such a defect. However, placing a plug intothe AF that much resist much higher pressures may result in expulsion ofthe plug or dissection of the inner layers of the annulus by the NP.Either complication would lead to extraordinary pain or loss of functionfor the patient. Further, a hernia in the intervertebral disc is likelyto spread as the AF progressively weakens. In such an instance, the plugmay be expelled into the epidural space.

Another hernia repair device involves a curved prosthetic mesh for usein inguinal hernias. The device includes a sheet of material that has aconvex side and a concave side and further embodiments with bothspherical and conical sections. This device may be well suited foringuinal hernias, but the shape and stiffness of the disclosedembodiments are less than optimal for application in hernias of theintervertebral disc. Hernias tend to be broader (around thecircumference of the disc) than they are high (the distance between theopposing vertebrae), a shape that does not lend itself to closure bysuch conical or spherical patches.

Another device involves an inflatable, barbed balloon patch used forclosing inguinal hernias. This balloon is left inflated within thedefect. A disadvantage of this device is that the balloon must remaininflated for the remainder of the patient's life to insure closure ofthe defect. Implanted, inflated devices rarely endure long periodswithout leaks, particularly when subjected to high loads. This is trueof penile prostheses, breast implants, and artificial sphincters.

Also known is a method of closing inguinal hernias. The method involvesapplying both heat and pressure to a planar patch and the abdominal wallsurrounding the hernia. This method has the drawback of relying entirelyon the integrity of the wall surrounding the defect to hold the patch inplace. The annulus is often weak in areas around a defect and may notserve as a suitable anchoring site. Further, the planar nature of thepatch has all of the weaknesses discussed above.

Various devices and techniques have further been disclosed for sealingvascular puncture sites. The most relevant include a hemostatic puncturesealing device that generally consists of an anchor, a filament and asealing plug. The anchor is advanced into a vessel through a defect anddeployed such that it resists passage back through the defect. Afilament leading from the anchor and through the defect can be used tosecure the anchor or aid in advancing a plug that is brought against theexterior of the defect. Certain devices employ a filament brought backthrough the defect. Such a filament, if it were to extend to theexterior of the disc, could lead to irritation of nerve roots and theformation of scar tissue in the epidural space. This is also true of anyplug material that may be left either within the defect or extending tothe exterior of the disc. The exterior portion of an exposed filamentcould abrade nerve tissue and lead to pain and scar formation within theepidural space. Additionally, devices and methods embodied for use inthe vascular system and would be hard to implement in the disc and wouldrequire a space relatively empty of solids for the deployment of theinterior anchor. This works well on the interior of a vessel, however,in the presence of the more substantial NP, the disclosed internalanchors are unlikely to orient across the defect as disclosed in theirinventions.

SUMMARY OF THE INVENTION

It is the object of the disclosed invention to reduce the long-termnegative consequences of herniated discs by repairing and/or augmentingrather than resecting the soft tissues of the disc. Repairing a tear inthe AF can accompany this method, but is not necessary for achieving thepurpose of the disclosed invention. It is a further object of thisinvention to prevent or reduce the occurrence of re-herniation and discheight loss following surgical therapy for herniated discs. It is afurther object of this invention to increase the AF's resistance toposterior bulging and leakage of NP material while increasing itsstiffness under load. It is a further object of this invention to permitthe augmentation of the soft tissues of the disc in such away so as tolimit the risk of the herniation of any augmentation materials towardnerve structures posterior to the disc.

In one aspect of the present invention there is provided an in vivoaugmented functional spine unit. The augmented functional spine unitincludes the two adjoining vertebra and the intervertebral disc,composed of a central region surrounded by an anterior fibrosis andsituated in the intervertebral disc space between the vertebra, and adisc herniation constraining device situated within the intervertebraldisc space. A disc herniation constraining device includes an anchorfixedly coupled to an anterior portion of one of the adjoining vertebraor annulus fibrosis and is connected to a support member by a connectingmember. The support member is positioned posterior to the centralregion, preferably in or posterior to the annulus fibrosis. In oneembodiment the central region of the functional spine unit contains anucleus pulposus. In another embodiment of the invention, the connectionmember is maintained under tension between the anchor and the supportmember. In yet another embodiment, augmentation material is securedalong at least a portion of the length of the connection member, whichserves to assist the function of the intervertebral disk in supportingand separating the vertebrae, and allowing motion of one vertebrarelative to the other.

In another aspect of the invention there is provided an in vivoaugmented functional spine unit. The augmented functional spine unitincludes the two adjoining vertebra and the intervertebral disc,composed of a central region surrounded by an annulus fibrosis andsituated in the intervertebral disc space between the vertebra, and adisc augmentation device situated within the intervertebral disc space.The disc augmentation device includes an anchor fixedly coupled to ananterior portion of one of the adjoining vertebra or annulus fibrosis,augmentation material situated in the intervertebral disc space andrestrained therein by a connection member secured between the anchor andthe augmentation material. In an alternate embodiment, a support memberis secured within the functional spine unit, the connection memberextends between the anchor, the augmentation material and the supportmember, further restraining the movement of the augmentation materialwithin the central region. In yet another embodiment, the central regionmay contain a nucleus pulposus.

In yet another aspect of the present invention there are providedmethods of augmenting a functional spine unit. These methods includeusing the disc herniation constraining devices and the disc augmentationdevices disclosed herein.

The present invention further relates to devices and methods for sealingdefects in tissue walls separating two anatomic regions of the body.Specifically, prosthetic devices and methods are disclosed which allowthe closure of a defect in the AF of the human intervertebral disc,preventing the egress of material from within the disc and/ordistributing pressure within the disc space across an inner wall surfaceof the discs.

Each aspect of the present invention relates to placing a membrane orbarrier on an interior aspect of the defect. In the case of theintervertebral disc, the barrier means is positioned on the interioraspect of the AF proximate to the NP. The barrier means may be insertedby dissecting a space between the annulus and nucleus. Alternatively, aportion of the nucleus and/or annulus may be resected to create adequatespace.

The barrier may be inserted into position directly through the defect oralternatively it may be advanced from a remote entry through the tissuewall or another tissue neighboring the defect.

Various fixation devices can be used to secure the barrier tosurrounding tissues. In the IV disc, these tissues can included thesurrounding AF, vertebral endplates, vertebral bodies, and even NP.Alternatively, the barrier can be held in place simply by the pressurethe NP exerts on the barrier and AF shape of the patch may help tomaintain position and orientation within the disc. The barrier mayfurther incorporate various self-retaining members that resist motion ofthe barrier within the disc. Separate fixation devices may also beemployed to secure the barrier means to surrounding tissues. The barrieror membrane may incorporate a frame that can serve to enlarge or expandthe dimensions of the barrier from a compressed state to an enlargedstate. The barrier may further have properties that cause it to adhereto surrounding tissues upon the application of heat such as bycontaining an adhesive; e.g. fibrin glue. Various embodiments of thedisclosed barrier means are composed of either singular materials andcomponents or a multiplicity of materials and components.

However, implanting prostheses along the inner aspect of the annulusfibrosis is a challenging task. The interior of the disc is not visibleto the surgeon during standard posterior spinal procedures. Very littleof the exterior of the disc can be seen through the small window createdby the surgeon in the posterior elements of the vertebra to gain accessto the disc. The surgeon further tries to minimize the size of anyannular fenestration into the disc in order to reduce the risk ofpostoperative herniation and/or further destabilization of the operatedlevel. Surgeons generally only open one side of the posterior annulus inorder to avoid scarring on both sides of the epidural space.

These rigorous requirements presented by these limitations on access toand visualization of the disc are not well compensated for by any of theintradiscal prosthesis implantation systems currently available.

It is the object of the present invention to reduce the limitations ofcurrent implant delivery systems. It is a further object of the presentinvention to provide systems and methods for implanting a prosthesisalong the interior aspect of the annulus through a single, smallannulotomy from the posterior aspect of the disc.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1A shows an axial view of a portion of a functional spine unit, inwhich part of a vertebra and intervertebral disc are depicted;

FIG. 1B shows an sagittal cross section of a portion of a functionalspine unit shown in FIG. 1A, in which two lumbar vertebrae and theintervertebral disc are visible;

FIG. 2A shows an axial view of one aspect of the invention showing aportion of the FSU prior to supporting a herniated segment;

FIG. 2B shows an axial view of the construct in FIG. 2A supporting theherniated segment;

FIG. 3A shows an axial view of another embodiment of the disclosedinvention after placement of the device;

FIG. 3B shows an axial view of the construct in FIG. 3a after tension isapplied to support the herniated segment;

FIG. 4A shows an axial view of an alternate embodiment of the invention;

FIG. 4B shows a sagittal view of the alternate embodiment shown in FIG.,4A;

FIG. 5A shows an axial view of another aspect of the present invention.

FIG. 5B shows the delivery tube of FIG. 5A being used to displace theherniated segment to within its pre-herniated borders;

FIG. 5C shows a one-piece embodiment of the invention in an anchored andsupporting position;

FIG. 6 shows one embodiment of the invention supporting a weakenedposterior annulus fibrosis;

FIG. 7A shows an axial view of another aspect of the disclosed inventiondemonstrating two stages involved in augmentation of the soft tissues ofthe disc;

FIG. 7B shows a sagittal view of the invention shown in FIG., 7A;

FIG. 8 shows an axial view of one aspect of the disclosed inventioninvolving augmentation of the soft tissues of the disc andsupport/closure of the annulus fibrosis;

FIG. 9A shows an axial view of one aspect of the invention involvingaugmentation of the soft tissues of the disc with the flexibleaugmentation material anchored to the anterior lateral annulus fibrosis;

FIG. 9B shows an axial view of one aspect of the disclosed inventioninvolving augmentation of the soft tissues of the disc with the flexibleaugmentation material anchored to the annulus fibrosis by a one pieceanchor;

FIG. 10A shows an axial view of one aspect of the disclosed inventioninvolving augmentation of the soft tissues of the disc; and

FIG. 10B shows the construct of FIG. 10A after the augmentation materialhas been inserted into the disc.

FIG. 11 illustrates an axial view of a barrier mounted within anannulus.

FIG. 12 shows a sagittal view of the barrier of FIG. 11.

FIG. 13 shows an axial view of a barrier anchored within a disk.

FIG. 14 illustrates a sagittal view of the barrier shown in FIG. 13.

FIG. 15 illustrates the use of a second anchoring device for a barriermounted within a disk.

FIG. 16A is an axial (transverse) view of the intervertebral disk.

FIG. 16B is a sagittal section along the midline of the intervertebraldisk.

FIG. 17 is an axial view of the intervertebral disc with the right halfof a sealing means of a barrier means being placed against the interioraspect of a defect in annulus fibrosis by a dissection/delivery tool.

FIG. 18 illustrates a full sealing means placed on the interior aspectof a defect in annulus fibrosis.

FIG. 19 depicts the sealing means of FIG. 18 being secured to tissuessurrounding the defect.

FIG. 20 depicts the sealing means of FIG. 19 after fixation means havebeen passed into surrounding tissues.

FIG. 21A depicts an axial view of the sealing means of FIG. 20 havingenlarging means inserted into the interior cavity.

FIG. 21B depicts the construct of FIG. 21 in a sagittal section.

FIG. 22A shows an alternative fixation scheme for the sealing means andenlarging means.

FIG. 22B shows the construct of FIG. 22A in a sagittal section with ananchor securing a fixation region of the enlarging means to a superiorvertebral body in a location proximate to the defect.

FIG. 23A depicts an embodiment of the barrier means of the presentinvention being secured to annulus 10 using fixation means.

FIG. 23B depicts an embodiment of the barrier means of FIG. 23A securedto annulus by two fixation darts wherein the fixation tool has beenremoved.

FIGS. 24A and 24B depict a barrier means positioned between layers ofthe annulus fibrosis on either side of a defect.

FIG. 25 depicts an axial cross section of a large version of a barriermeans.

FIG. 26 depicts an axial cross section of a barrier means in positionacross a defect following insertion of two augmentation devices.

FIG. 27 depicts the barrier means as part of elongated augmentationdevice.

FIG. 28A depicts an axial section of an alternate configuration of theaugmentation device of FIG. 27.

FIG. 28B depicts a sagittal section of an alternate configuration of anaugmentation device of FIG. 27.

FIGS. 29A-D depict deployment of a barrier from entry site remote fromthe defect in annulus fibrosis.

FIGS. 30A and 30B, 31A and 31B, 32A and 32B and 33A and 33B depict axialand sectional views, respectively of embodiments of the barrier.

FIG. 34 shows a non-axisymmetric expansion means.

FIGS. 35 and 36 illustrate alternate embodiments of the expansion meansshown in FIG. 34.

FIGS. 37A, 37B and 37C illustrate a side, front, and perspective viewrespectively, of an alternate embodiment of expansion means shown inFIG. 34.

FIG. 38 shows an alternate expansion means to that shown in FIG. 37A.

FIGS. 39A-39D illustrate a tubular expansion means having a circularcross-section.

FIGS. 40A-40D illustrate a tubular expansion means having an oval shapedcross-section.

FIGS. 40E, 40F and 40I illustrate a front, back and top view,respectively of the tubular expansion means of FIG. 40A having a sealingmeans covering an exterior surface of an annulus face.

FIGS. 40G and 40H show the tubular expansion means of FIG. 40A having asealing means covering an interior surface of an annulus face.

FIGS. 41A-41D illustrate a tubular expansion means having an egg-shapedcross-section.

FIGS. 42A-D depict cross sections of a preferred embodiment of sealingmeans and enlarging means.

FIGS. 43A and 43B depict an alternative configuration of enlargingmeans.

FIGS. 44A and 44B depict an alternative shape of the barrier means.

FIG. 45 is a section of a device used to affix sealing means to tissuessurrounding a defect.

FIG. 46 depicts the use of thermal device to heat and adhere sealingmeans to issues surrounding a defect.

FIG. 47 depicts an expandable thermal element that can be used to adheresealing means to tissues surrounding a defect.

FIG. 48 depicts an alternative embodiment to the thermal device.

FIGS. 49A through 49G illustrate a method of implanting an intradiscalimplant.

FIGS. 50A through 50F show an alternate method of implanting anintradiscal implant.

FIGS. 51A through 51C show another alternate method of implanting anintradiscal implant.

FIGS. 52A and 52B illustrate an implant guide used with the intradiscalimplant system.

FIG. 53A illustrates a barrier having stiffening plate elements.

FIG. 53B illustrates a sectional view of the barrier of FIG. 53A.

FIG. 54A shows a stiffening plate.

FIG. 54B shows a sectional view of the stiffening plate of FIG. 54A.

FIG. 55A illustrates a barrier having stiffening rod elements.

FIG. 55B illustrates a sectional view of the barrier of FIG. 55A.

FIG. 56A illustrates a stiffening rod.

FIG. 56B illustrates a sectional view of the stiffening rod of FIG. 56A.

FIG. 57 shows an alternate configuration for the location of thefixation devices of the barrier of FIG. 44A.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for an in vivo augmented functional spineunit. A functional spine unit includes the bony structures of twoadjacent vertebrae (or vertebral bodies), the soft tissue (annulusfibrosis (AF), and optionally nucleus pulposus (NP)) of theintervertebral disc, and the ligaments, musculature and connectivetissue connected to the vertebrae. The intervertebral disc issubstantially situated in the intervertebral space formed between theadjacent vertebrae. Augmentation of the functional spine unit caninclude repair of a herniated disc segment, support of a weakened, tornor damaged annulus fibrosis, or the addition of material to orreplacement of all or part of the nucleus pulposus. Augmentation of thefunctional spine unit is provided by herniation constraining devices anddisc augmentation devices situated in the intervertebral disc space.

FIGS. 1A and 1B show the general anatomy of a functional spine unit 45.In this description and the following claims, the terms ‘anterior’ and‘posterior’, ‘superior’ and ‘inferior’ are defined by their standardusage in anatomy, i.e., anterior is a direction toward the front(ventral) side of the body or organ, posterior is a direction toward theback (dorsal) side of the body or organ; superior is upward toward thehead and inferior is lower or toward the feet.

FIG. 1A is an axial view (transverse) along transverse axis M of avertebral body with the intervertebral disc 15 superior to the vertebralbody. Axis M shows the anterior (A) and posterior (P) orientation of thefunctional spine unit within the anatomy. The intervertebral disc 15contains the annulus fibrosis (AF) 10 which surrounds a central nucleuspulposus (NP) 20. Herniated segment 30 is depicted by a dashed-line.Herniated segment 30 protrudes beyond the pre-herniated posterior border40 of the disc. Also shown in this figure are the left 70 and right 70′transverse spinus processes and the posterior spinus process 80.

FIG. 1B is a sagittal section along sagittal axis N through the midlineof two adjacent vertebral bodies 50 (superior) and 50′ (inferior).Intervertebral disc space 55 is formed between the two vertebral bodiesand contains intervertebral disc 15, which supports and cushions thevertebral bodies and permits movement of the two vertebral bodies withrespect to each other and other adjacent functional spine units.

Intervertebral disc 15 is comprised of the outer AF 10 which normallysurrounds and constrains the NP 20 to be wholly within the borders ofthe intervertebral disc space. In FIGS. 1A and 1B, herniated segment 30,represented by the dashed-line, has migrated posterior to thepre-herniated border 40 of the posterior AF of the disc. Axis M extendsbetween the anterior (A) and posterior (P) of the functional spine unit.The vertebral bodies also include facet joints 60 and the superior 90and inferior 90′ pedicle that form the neural foramen 100. Disc heightloss occurs when the superior vertebral body 50 moves inferiorlyrelative to the inferior vertebral body 50′.

In one embodiment of the present invention, the disc herniationconstraining devices 13 provide support for returning all or part of theherniated segment 30 to a position substantially within itspre-herniated borders 40. The disc herniation constraining deviceincludes an anchor which is positioned at a site within the functionalspine unit, such as the superior or inferior vertebral body, or theanterior, medial, or anterior lateral annulus fibrosis. The anchor isused as a point against which all or part of the herniated segment istensioned so as to return the herniated segment to its pre-herniatedborders, and thereby relieve pressure on otherwise compressed neuraltissue and structures. A support member is positioned in or posterior tothe herniated segment, and is connected to the anchor by a connectingmember. Sufficient tension is applied to the connecting member so thatthe support member returns the herniated segment to a pre-herniatedposition. In various embodiments, augmentation material is securedwithin the intervertebral disc space, which provides assists the NP incushioning and supporting the inferior and superior vertebral bodies. Ananchor secured in a portion of the functional spine unit and attached toconnection member and augmentation material, limits movement of theaugmentation material within the intervertebral disk space. A supportingmember, located opposite the anchor, may optionally provide a secondpoint of attachment for the connecting member and further hinder themovement of the augmentation material within the intervertebral diskspace.

FIGS. 2A and 2B depict one embodiment of device 13. FIG. 2A shows theelements of the constraining device in position to correct the herniatedsegment. Anchor 1 is securely established in a location within thefunctional spine unit, such as the anterior AF shown in the figure.Support member 2 is positioned in or posterior to herniated segment 30.Leading from and connected to anchor 1 is connection member 3, whichserves to connect anchor 1 to support member 2. Depending on thelocation chosen for support member 2, the connection member may traversethrough all or part of the herniated segment.

FIG. 2B shows the positions of the various elements of the herniationconstraining device 13 when the device 13 is supporting the herniatingsegment. Tightening connection member 2 allows it to transmit tensileforces along its length, which causes herniated segment 30 to moveanteriorly, i.e., in the direction of its pre-herniated borders. Onceherniated segment 30 is in the desired position, connection member 3 issecured in a permanent fashion between anchor 1 and support member 2.This maintains tension between anchor 1 and support member 2 andrestricts motion of the herniated segment to within the pre-herniatedborders 40 of the disc. Support member 2 is used to anchor to herniatedsegment 30, support a weakened AF in which no visual evidence ofherniation is apparent, and it may also be used to close a defect in theAF of herniated segment 30.

Anchor 1 is depicted in a representative form because it can take one ofmany forms, be made from one of a variety of biocompatible materials,and be constructed so as to have one of a range of stiffness. It can bea permanent device constructed of durable plastic or metal or can bemade from a resorbable material such as polylactic acid (PLA) orpolyglycolic acid (PGA). Specific embodiments are not shown, but manypossible designs would be obvious to anyone skilled in the art.Embodiments include, but are not limited to, a barbed anchor made of PLAor a metal coil that can be screwed into the anterior AF. Anchor 1 canbe securely established within a portion of the functional spine unit inthe usual and customary manner for such devices and locations, such asbeing screwed into bone, sutured into tissue or bone, or affixed totissue or bone using an adhesive method, such as cement, and suitablesurgical adhesives. Once established within the bone or tissue, anchor 1should remain relatively stationary within the bone or tissue.

Support member 2 is also depicted in a representative format and sharesthe same flexibility in material and design as anchor 1. Both deviceelements can be of the same design, or they can be of different designs,each better suited to being established in healthy and diseased tissuerespectively. Alternatively, in other forms, support member 2 can be acap or a bead shape, which also serves to secure a tear or puncture inthe AF, or it can be bar or plate shaped, with or without barbs tomaintain secure contact with the herniated segment. Support member 2 canbe established securely to, within, or posterior to the herniatedsegment.

The anchor and support member can include suture, bone anchors, softtissue anchors, tissue adhesives, and materials that support tissueingrowth although other forms and materials are possible. They may bepermanent devices or resorbable. Their attachment to a portion of FSUand herniated segment must be strong enough to resist the tensionalforces that result from repair of the hernia and the loads generatedduring daily activities.

Connection member 3 is also depicted in representative fashion. Member 3may be in the format of a flexible filament, such as a single ormulti-strand suture, wire, or maybe a rigid rod or broad band ofmaterial, for example. The connection member can further include suture,wire, pins, and woven tubes or webs of material. It can be constructedfrom a variety of materials, either permanent or resorbable, and can beof any shape suitable to fit within the confines of the intervertebraldisc space. The material chosen is preferably adapted to be relativelystiff while in tension, and relatively flexible against all other loads.This allows for maximal mobility of the herniated segment relative tothe anchor without the risk of the supported segment moving outside ofthe pre-herniated borders of the disc. The connection member may be anintegral component of either the anchor or support member or a separatecomponent. For example, the connection member and support member couldbe a length of non-resorbing suture that is coupled to an anchor, andtensioned against the anchor, and sewn to the herniated segment.

FIGS. 3A and 3B depict another embodiment of device 13. In FIG. 3A theelements of the herniation constraining device are shown in positionprior to securing a herniated segment. Anchor 1 is positioned in the AF,and connection member 3 is attached to anchor 1. Support member 4 ispositioned posterior to the posterior-most aspect of herniated segment30. In this way, support member 4 does not need to be secured inherniated segment 30 to cause herniated segment 30 to move within thepre-herniated borders 40 of the disc. Support member 4 has the sameflexibility in design and material as anchor 1, and may further take theform of a flexible patch or rigid plate or bar of material that iseither affixed to the posterior aspect of herniated segment 30 or issimply in a form that is larger than any hole in the AF directlyanterior to support member 4. FIG. 3B shows the positions of theelements of the device when tension is applied between anchor 1 andsupport member 4 along connection member 3. The herniated segment isdisplaced anteriorly, within the pre-herniated borders 40 of the disc.

FIGS. 4A and 4B show five examples of suitable anchoring sites withinthe FSU for anchor 1. FIG. 4A shows an axial view of anchor 1 in variouspositions within the anterior and lateral AF. FIG. 4B similarly shows asagittal view of the various acceptable anchoring sites for anchor 1.Anchor 1 is secured in the superior vertebral body 50, inferiorvertebral body 50′ or anterior AF 10, although any site that canwithstand the tension between anchor 1 and support member 2 alongconnection member 3 to support a herniated segment within itspre-herniated borders 40 is acceptable.

Generally, a suitable position for affixing one or more anchors is alocation anterior to the herniated segment such that, when tension isapplied along connection member 3, herniated segment 30 is returned to asite within the pre-herniated borders 40. The site chosen for the anchorshould be able to withstand the tensile forces applied to the anchorwhen the connection member is brought under tension. Because mostsymptomatic herniations occur in the posterior or posterior lateraldirections, the preferable site for anchor placement is anterior to thesite of the herniation. Any portion of the involved FSU is generallyacceptable, however the anterior, anterior medial, or anterior lateralAF is preferable. These portions of the AF have been shown to haveconsiderably greater strength and stiffness than the posterior orposterior lateral portions of the AF. These portions of the AF are alsomore flexible than the superior and inferior vertebral bodies and willallow greater mobility of the supported herniated segment. As shown inFIGS. 4A and 4B, anchor 1 can be a single anchor in any of the shownlocations, or there can be multiple anchors 1 affixed in variouslocations and connected to a support member 2 to support the herniatedsegment. Connection member 3 can be one continuous length that isthreaded through all the sited anchors and the support member, or it canbe several individually strands of material each terminated undertension between an anchor and one or more support members.

In various forms of the invention, the anchor(s) and connection membermay be introduced and installed in the patient, with the connectionmember under tension. Alternatively, those elements may be installed,without introducing tension to the connection member, but where theconnection member is adapted to be under tension when the patient is ina non-horizontal position, i.e., resulting from loading in the IV disc.

FIGS. 5A, B, and C show an alternate embodiment of herniationconstraining device 13 a. In this series of figures, device 13 a, asubstantially one-piece construct, is delivered through a delivery tube6, although device 13 a could be delivered in a variety of waysincluding, but not limited to, by hand or by a hand held graspinginstrument. In FIG. 5A, device 13 a in delivery tube 6 is positionedagainst herniated segment 30. In FIG. 5B, the herniated segment isdisplaced within its pre-herniated borders 40 by device 13 a and/ordelivery tube 6 such that when, in FIG. 5C, device 13 a has beendelivered through delivery tube 6, and secured within a portion of theFSU, the device supports the displaced herniated segment within itspre-herniated border 40. Herniation constraining device 13 a can be madeof a variety of materials and have one of many possible forms so long asit allows support of the herniated segment 30 within the pre-herniatedborders 40 of the disc. Device 13 a can anchor the herniated segment 30to any suitable anchoring site within the FSU, including, but notlimited to the superior vertebral body, inferior vertebral body, oranterior AF. Device 13 a may be used additionally to close a defect inthe AF of herniated segment 30. Alternatively, any such defect may beleft open or may be closed using another means.

FIG. 6 depicts the substantially one-piece device 13 a supporting aweakened segment 30′ of the posterior AF 10′. Device 13 a is positionedin or posterior to the weakened segment 30′ and secured to a portion ofthe FSU, such as the superior vertebral body 50, shown in the figure, orthe inferior vertebral body 50′ or anterior, medial, anterior lateralannulus fibrosis 10. In certain patients, there may be no obviousherniation found at surgery. However, a weakened or torn AF that may notto be protruding beyond the pre-herniated borders of the disc may stillinduce the surgeon to remove all or part of the NP in order to decreasethe risk of herniation. As an alternative to discectomy, any of theembodiments of the invention may be used to support and perhaps closedefects in or weakened segments of AF.

A further embodiment of the present invention involves augmentation ofthe soft tissues of the intervertebral disc to avoid or reverse discheight loss. FIGS. 7A and 7B show one embodiment of device 13 securingaugmentation material in the intervertebral disc space 55. In the leftside of FIG. 7A, anchors 1 have been established in the anterior AF 10.Augmentation material 7 is in the process of being inserted into thedisc space along connection member 3 which, in this embodiment, haspassageway 9. Support member 2′ is shown ready to be attached toconnection member 3 once the augmentation material 7 is properlysituated. In this embodiment, connection member 3 passes through anaperture 11 in support member 2′, although many other methods ofaffixing support member 2′ to connection member 3 are possible andwithin the scope of this invention.

Augmentation material 7 may have a passageway 9, such as a channel, slitor the like, which allows it to slide along the connection member 3, oraugmentation material 7 may be solid, and connection member 3 can bethreaded through augmentation material by means such as needle or otherpuncturing type device. Connection member 3 is affixed at one end toanchor 1 and terminated at its other end by a support member 2′, oneembodiment of which is shown in the figure in a cap-like configuration.Support member 2′ can be affixed to connection member 3 in a variety ofways, including but not limited, to swaging support member 2′ toconnection member 3. In a preferred embodiment, support member 2′ is ina cap configuration and has a dimension (diameter or length and width)larger than the optional passageway 9, which serves to preventaugmentation material 7 from displacing posteriorly with respect toanchor 1. The right half of the intervertebral disc of FIG. 7A (in axialview) and FIG. 7B (in sagittal view) show augmentation material 7 thathas been implanted into the disc space 55 along connection member 3where it supports the vertebral bodies 50 and 50′. FIG. 7A shows anembodiment in which support member 2′ is affixed to connection member 3and serves only to prevent augmentation material 7 from moving offconnection member 3. The augmentation device is free to move within thedisc space. FIG. 7B shows an alternate embodiment in which supportmember 2′ is embedded in a site in the functional spine unit, such as aherniated segment or posterior annulus fibrosis, to further restrict themovement of augmentation material 7 within the disc space.

Augmentation material can be made of any biocompatible, preferablyflexible, material. Such a flexible material is preferably fibrous, likecellulose or bovine or autologous collagen. The augmentation materialcan be shaped like plugs, discs, cubelike, ellipsoid, spheroid or anyother suitable shape. The augmentation material can be secured withinthe intervertebral space by a variety of methods, such as but notlimited to, a suture loop attached to, around, or through the material,which is then passed to the anchor and support member.

FIGS. 8, 9A, 9B and 10A and 10B depict further embodiments of the discherniation constraining device 13 b in use for augmenting soft tissue,particularly tissue within the intervertebral space. In the embodimentsshown in FIGS. 8 and 9A, device 13B is secured within the intervertebraldisc space providing additional support for NP 20. Anchor 1 is securelyaffixed in a portion of the FSU, (anterior AF 10 in these figures).Connection member 3 terminates at support member 2, preventingaugmentation material 7 from migrating generally posteriorly withrespect to anchor 1. Support member 2 is depicted in these figures asestablished in various locations, such as the posterior AF 10′ in FIG.8, but support member 2 may be anchored in any suitable location withinthe FSU, as described previously. Support member 2 may be used to closea defect in the posterior AF. It may also be used to displace aherniated segment to within the pre-herniated borders of the disc byapplying tension between anchoring means 1 and 2 along connection member3.

FIG. 9A depicts anchor 1, connection member 3, augmentation material 7and support member 2′ (shown in the “cap”-type configuration) insertedas a single construct and anchored to a site within the disc space, suchthe inferior or superior vertebral bodies. This configuration simplifiesinsertion of the embodiments depicted in FIGS. 7 and 8 by reducing thenumber of steps to achieve implantation. Connection member 3 ispreferably relatively stiff in tension, but flexible against all otherloads. Support member 2′ is depicted as a bar element that is largerthan passageway 9 in at least one plane.

FIG. 9B depicts a variation on the embodiment depicted in FIG. 9A. FIG.9B shows substantially one-piece disc augmentation device 13C, securedin the intervertebral disc space. Device 13C has anchor 1, connectionmember 3 and augmentation material 7. Augmentation material 7 and anchor1 could be pre-assembled prior to insertion into the disc space 55 as asingle construct. Alternatively, augmentation material 7 could beinserted first into the disc space and then anchored to a portion of theFSU by anchor 1.

FIGS. 10A and 10B show yet another embodiment of the disclosedinvention, 13D. In FIG. 10A, two connection members 3 and 3′ areattached to anchor 1. Two plugs of augmentation material 7 and 7′ areinserted into the disc space along connection members 3 and 3′.Connection members 3 and 3′ are then bound together (i.e., knottedtogether, fused or the like). This forms loop 3″ that serves to preventaugmentation materials 7 and 7′ from displacing posteriorly. FIG. 10Bshows the position of the augmentation material 7 after it is secured bythe loop 3″ and anchor 1. Various combinations of augmentation material,connecting members and anchors can be used in this embodiment, such asusing a single plug of augmentation material, or two connection membersleading from anchor 1 with each of the connection members being bound toat least one other connection member. It could further be accomplishedwith more than one anchor with at least one connection member leadingfrom each anchor, and each of the connection members is be bound to atleast one other connection member.

Any of the devices described herein can be used for closing defects inthe AF whether created surgically or during the herniation event. Suchmethods may also involve the addition of biocompatible material toeither the AF or NP. This material could include sequestered or extrudedsegments of the NP found outside the pre-herniated borders of the disc.

FIGS. 11-15 illustrate devices used in and methods for closing a defectin an annulus fibrosis. One method involves the insertion of a barrieror barrier means 12 into the disc 15. This procedure can accompanysurgical discectomy. It can also be done without the removal of anyportion of the disc 15 and further in combination with the insertion ofan augmentation material or device into the disc 15.

The method consists of inserting the barrier means 12 into the interiorof the disc 15 and positioning it proximate to the interior aspect ofthe annular defect 16. The barrier material is preferably considerablylarger in area than the size of the defect 16, such that at least someportion of the barrier means 12 abuts healthier annulus fibrosis 10. Thedevice acts to seal the annular defect 16, recreating the closedisobaric environment of a healthy disc nucleus 20. This closure can beachieved simply by an over-sizing of the implant relative to the defect16. It can also be achieved by affixing the barrier means 12 to tissueswithin the functional spinal unit. In preferred aspect of the presentinvention, the barrier 12 is affixed to the annulus surrounding theannular defect 16. This can be achieved with sutures, staples, glues orother suitable fixation means or fixation device 14. The barrier means12 can also be larger in area than the defect 16 and be affixed to atissue or structure opposite the defect 16, i.e. anterior tissue in thecase of a posterior defect.

The barrier means 12 is preferably flexible in nature. It can beconstructed of a woven material such as Dacron or Nylon and can furtherbe an expanded material, such as expanded polytetrafluroethelene(e-PTFE), for example. The barrier means 12 can also be a biologicmaterial such as cross-linked collagen or cellulous.

The barrier means 12 can be a single piece of material. It can have anexpandable means or component that allows it to be expanded from acompressed state after insertion into the interior of the disc 15. Thisexpandable means can be active, such as a balloon, or passive, such as ahydrophilic material. The expandable means can also be a self expandingmesh of elastically deforming material, for example.

FIGS. 11 and 12 illustrate a barrier 12 mounted within an annulus 10 andcovering an annular defect 16. The barrier 12 can be secured to theannulus 10 with a fixation mechanism or fixation means 14. The fixationmeans 14 can include a plurality of suture loops placed through thebarrier 12 and the annulus 10. Such fixation can prevent motion orslipping of the barrier 12 away from the annular defect 16.

The barrier means 12 can also be anchored to the disc 15 in multiplelocations. In one preferred embodiment, shown in FIGS. 13 and 14, thebarrier means 12 can be affixed to the annular tissue 10 in orsurrounding the defect and further affixed to a secondary fixation siteopposite the defect, i.e. the anterior annulus 10 in a posteriorherniation or the inferior 50′ or superior 50 vertebral body. Forexample, fixation means 14 can be used to attach the barrier 12 to theannulus 10 near the defect 16, while an anchoring mechanism 18 cansecure the barrier 12 to a secondary fixation site. A connector 22 canattach the barrier 12 to the anchor 18. Tension can be applied betweenthe primary and secondary fixation sites through a connector 22 so as tomove the annular defect 16 toward the secondary fixation site. This maybe particularly beneficial in closing defects 16 that result inposterior herniations. By using this technique, the herniation can bemoved and supported away from any posterior neural structures whilefurther closing any defect in the annulus 10.

The barrier means 12 can further be integral to a fixation means suchthat the barrier means affixes itself to tissues within the functionalspinal unit.

Any of the methods described above can be augmented by the use of asecond barrier or a second barrier means 24 placed proximate to theouter aspect of the defect 16 as shown in FIG. 15. The second barrier 24can further be affixed to the inner barrier means 12 by the use of afixation means 14 such as suture material.

FIGS. 16A and 16B depicts intervertebral disc 15 comprising nucleuspulposus 20 and annulus fibrosis 10. Nucleus pulposus 20 forms a firstanatomic region and extra-discal space 500 (any space exterior to thedisc) forms a second anatomic region wherein these regions are separatedby annulus 10.

FIG. 16A is an axial (transverse) view of the intervertebral disc. Aposterior lateral defect 16 in annulus fibrosis 10 has allowed a segment30 of nucleus pulposus 20 to herniate into an extra discal space 500.Interior aspect 32 and exterior aspect 34 are shown, as are the right70′ and left 70 transverse processes and posterior process 80.

FIG. 16B is a sagittal section along the midline intervertebral disc.Superior pedicle 90 and inferior pedicle 90′ extend posteriorly fromsuperior vertebral body 95 and inferior vertebral body 95′ respectively.

To prevent further herniation of the nucleus 20 and to repair anypresent herniation, in a preferred embodiment, a barrier or barriermeans 12 can be placed into a space between the annulus 10 and thenucleus 20 proximate to the inner aspect 32 of defect 16, as depicted inFIGS. 17 and 18. The space can be created by blunt dissection.Dissection can be achieved with a separate dissection instrument, withthe barrier means 12 itself, or a combined dissection/barrier deliverytool 100. This space is preferably no larger than the barrier means suchthat the barrier means 12 can be in contact with both annulus 10 andnucleus 20. This allows the barrier means 12 to transfer load from thenucleus 20 to the annulus 10 when the disc is pressurized duringactivity.

In position, the barrier means 12 preferably spans the defect 16 andextends along the interior aspect 36 of the annulus 10 until it contactshealthy tissues on all sides of the defect 16. Depending on the extentof the defect 16, the contacted tissues can include the annulus 10,cartilage overlying the vertebral endplates, and/or the endplatesthemselves.

In the preferred embodiment, the barrier means 12 consists of twocomponents a sealing means or sealing component 51 and an enlargingmeans or enlarging component 53, shown in FIGS. 21A and 21B.

The sealing means 51 forms the periphery of the barrier 12 and has aninterior cavity 17. There is at least one opening 8 leading into cavity17 from the exterior of the sealing means 51. Sealing means 51 ispreferably compressible or collapsible to a dimension that can readilybe inserted into the disc 15 through a relatively small hole. This holecan be the defect 16 itself or a site remote from the defect 16. Thesealing means 51 is constructed from a material and is formed in such amanner as to resist the passage of fluids and other materials aroundsealing means 51 and through the defect 16. The sealing means 51 can beconstructed from one or any number of a variety of materials including,but not limited to PTFE, e-PTFE, Nylon TM, Marlex TM, and/or collagen.

The enlarging means 53 can be sized to fit within cavity 17 of sealingmeans 51. It is preferably a single object of a dimension that can beinserted through the same defect 16 through which the sealing means 51was passed. The enlarging means 53 can expand the sealing means 51 to anexpanded state as it is passed into cavity 17. One purpose of enlargingmeans 53 is to expand sealing means 51 to a size greater than that ofthe defect 16 such that the assembled barrier 12 prevents passage ofmaterial through the defect 16. The enlarging component 53 can furtherimpart stiffness to the barrier means 12 such that the barrier means 12will resist the pressures within nucleus pulposus 20 and expulsionthrough the defect 16. The enlarging means 53 can be constructed fromone or any number of materials including, but not limited to siliconrubber, various plastics, stainless steel, NITINOL or other metals.These materials may form a solid object, a hollow object, coiled springsor other suitable forms capable of filling cavity 17 within sealingmeans 51.

The sealing means 51, enlarging means 53, or the barrier means 12construct can further be affixed to tissues either surrounding thedefect 16 or remote from the defect 16. In the preferred embodiment, noaspect of a fixation means or fixation device or the barrier means 12and its components extends posterior to the disc 15 and into the secondanatomic region 500. This avoids the risk of contacting and irritatingthe sensitive nerve tissues posterior to the disc 15.

In a preferred embodiment, the sealing means 51 is inserted into thedisc 15 proximate the interior aspect 36 of the defect. The sealingmeans 51 is then affixed to the tissues surrounding the defect using asuitable fixation means, such as suture or a soft-tissue anchor. Thefixation procedure is preferably performed from the interior of thesealing means cavity 17 as depicted in FIGS. 19 and 20. A fixationdelivery instrument 110 is delivered into cavity 17 through opening 8 inthe sealing means 51. Fixation devices 14 can then be deployed through awall of the sealing means 53 into surrounding tissues. Once the fixationmeans 14 have been passed into surrounding tissue, the fixation deliveryinstrument 110 can be removed from the disk 15. This method eliminatesthe need for a separate entryway into the disc 15 for delivery offixation means 14. It further minimizes the risk material leakingthrough sealing means 51 proximate to the fixation means 14. One or morefixation means 14 can be delivered into one or any number of surroundingtissues including the superior 95 and inferior 95′ vertebral body.Following fixation of the sealing means 51, the enlarging means 53 canbe inserted into cavity 17 of the sealing means 51 to further expand thebarrier means 12 construct as well as increase its stiffness, asdepicted in FIGS. 21A and 21B. The opening 8 into the sealing means 51can then be closed by a suture or other means, although this is not arequirement of the present invention. In certain cases, insertion of aseparate enlarging means may not be necessary if adequate fixation ofthe sealing means 51 is achieved.

Another method of securing the barrier 12 to tissues is to affix theenlarging means 53 to tissues either surrounding or remote from thedefect 16. The enlarging means 53 can have an integral fixation region 4that facilitates securing it to tissues as depicted in FIGS. 22A, 22B32A and 43B. This fixation region 4 can extend exterior to sealing means51 either through opening 8 or through a separate opening. Fixationregion 4 can have a hole through which a fixation means or fixationdevice 14 can be passed. In a preferred embodiment, the barrier 12 isaffixed to at least one of the surrounding vertebral bodies (95, 95′)proximate the defect using a bone anchor 14′. The bone anchor 14′ can bedeployed into the vertebral bodies 50, 50′ at some angle between 0° and180° relative to a bone anchor deployment tool. As shown the bone anchor14′ is mounted at 90° relative to the bone anchor deployment tool.Alternatively, the enlarging means 53 itself can have an integralfixation device 14 located at a site or sites along its length.

Another method of securing the barrier means 12 is to insert the barriermeans 12 through the defect 16 or another opening into the disc 15,position it proximate the interior aspect 36 of the defect 16, and passat least one fixation means 14 through the annulus 10 and into thebarrier 12. In a preferred embodiment of this method, the fixation means14 can be darts 15 and are first passed partially into annulus 10 withina fixation device 120, such as a hollow needle. As depicted in FIGS. 23Aand 23B, fixation means 25 can be advanced into the barrier means 12 andfixation device 120 removed. Fixation means 25 preferably have two ends,each with a means to prevent movement of that end of the fixationdevice. Using this method, the fixation means can be lodged in both thebarrier 12 and annulus fibrosis 10 without any aspect of fixation means25 exterior to the disc in the second anatomic region 500.

In another aspect of the present invention, the patch or barrier 12 canbe placed between two neighboring layers of the annulus 10 on eitherside of the defect 16 as depicted in FIGS. 24A and 24B. FIG. 24A showsan axial view while 24B shows a sagittal cross section. Such positioningspans the defect 16. The barrier means 12 can be secured using themethods outlined.

Another embodiment of the barrier 12 for spinal applications is a patchhaving a length, oriented along the circumference of the disk, which issubstantially greater than its height, which is oriented along thedistance separating the surrounding vertebral bodies. A barrier 12having a length greater than its height is illustrated in FIG. 25. Thebarrier 12 can be positioned across the defect 16 as well as theentirety of the posterior aspect of the annulus fibrosis 10. Suchdimensions of the barrier 12 can help to prevent the barrier 12 fromslipping after insertion and can aid in distributing the pressure of thenucleus 20 evenly along the posterior aspect of the annulus 10.

The barrier 12 can be used in conjunction with an augmentation device 11inserted within the annulus 10. The augmentation device 11 can includeseparate augmentation devices 42 as shown in FIG. 26. The augmentationdevice 11 can also be a single augmentation device 44 and can form partof the barrier 12 as barrier region 300, coiled within the annulusfibrosis 10, as shown in FIG. 27. Either the barrier 12 or barrierregion 300 can be secured to the tissues surrounding the defect 16 byfixation devices or darts 25.

In another embodiment of the present invention, the barrier or patch 12may be used as part of a method to augment the intervertebral disc. Inone aspect of this method, augmentation material or devices are insertedinto the disc through a defect (either naturally occurring or surgicallygenerated). Many suitable augmentation materials and devices arediscussed above and in the prior art. As depicted in FIG. 26, thebarrier means is then inserted to aid in closing the defect and/or toaid in transferring load from the augmentation materials/devices tohealthy tissues surrounding the defect. In another aspect of thismethod, the barrier means is an integral component to an augmentationdevice. As shown in FIGS. 27, 28A and 28B, the augmentation portion maycomprise a length of elastic material that can be inserted linearlythrough a defect in the annulus. A region 300 of the length forms thebarrier means of the present invention and can be positioned proximateto the interior aspect of the defect once the nuclear space isadequately filled. Barrier region 300 may then be affixed to surroundingtissues such as the AF and/or the neighboring vertebral bodies using anyof the methods and devices described above.

FIGS. 28A and 28B illustrate an axial section of an alternateconfiguration of an augmentation device 38. In this embodiment, barrierregion 300 extends across the defect 16 and has fixation region 4facilitating fixation of the device 13 to superior vertebral body 50with anchor 14′.

FIGS. 29A-D illustrate the deployment of a barrier 12 from an entry site800 remote from the defect in the annulus fibrosis 10. FIG. 29A showsinsertion instrument 130 with a distal end positioned within the discspace occupied by nucleus pulposus 20. FIG. 29B depicts deliverycatheter 140 exiting the distal end of insertion instrument 130 withbarrier 12 on its distal end. Barrier 12 is positioned across theinterior aspect of the defect 16. FIG. 29C depicts the use of anexpandable barrier 12′ wherein delivery catheter 140 is used to expandthe barrier 12′ with balloon 150 (not seen) on its distal end. Balloon150 may exploit heat to further adhere barrier 12′ to surroundingtissue. FIG. 29D depicts removal of balloon 150 and delivery catheter140 from the disc space leaving expanded barrier means 12′ positionedacross defect 16.

Another method of securing the barrier means 12 is to adhere it tosurrounding tissues through the application of heat. In this embodiment,the barrier means 12 includes a sealing means 51 comprised of athermally adherent material that adheres to surrounding tissues upon theapplication of heat. The thermally adherent material can includethermoplastic, collagen, or a similar material. The sealing means 51 canfurther comprise a separate structural material that adds strength tothe thermally adherent material, such as a woven Nylon TM or Marlex TM.This thermally adherent sealing means preferably has an interior cavity17 and at least one opening 8 leading from the exterior of the barriermeans into cavity 17. A thermal device can be attached to the insertioninstrument shown in FIGS. 29C and 29D. The insertion instrument 130having a thermal device can be inserted into cavity 17 and used to heatsealing means 51 and surrounding tissues. This device can be a simplethermal element, such as a resistive heating coil, rod or wire. It canfurther be a number of electrodes capable of heating the barrier meansand surrounding tissue through the application of radio frequency (RF)energy. The thermal device can further be a balloon 150, 150′, as shownin FIG. 47, capable of both heating and expanding the barrier means.Balloon 150, 150′ can either be inflated with a heated fluid or haveelectrodes located about its surface to heat the barrier means with RFenergy. Balloon 150, 150′ is deflated and removed after heating thesealing means. These thermal methods and devices achieve the goal ofadhering the sealing means to the AF and NP and potentially othersurrounding tissues. The application of heat can further aid theprocedure by killing small nerves within the AF, by causing the defectto shrink, or by causing cross-linking and/or shrinking of surroundingtissues. An expander or enlarging means 53 can also be an integralcomponent of barrier 12 inserted within sealing means 51. After theapplication of heat, a separate enlarging means 53 can be inserted intothe interior cavity of the barrier means to either enlarge the barrier12 or add stiffness to its structure. Such an enlarging means ispreferably similar in make-up and design to those described above. Useof an enlarging means may not be necessary in some cases and is not arequired component of this method.

The barrier means 12 shown in FIG. 25 preferably has a primary curvatureor gentle curve along the length of the patch or barrier 12 that allowsit to conform to the inner circumference of the AF 10. This curvaturemay have a single radius R as shown in FIGS. 44A and 44B or may havemultiple curvatures. The curvature can be fabricated into the barrier 12and/or any of its components. For example, the sealing means can be madewithout an inherent curvature while the enlarging means can have aprimary curvature along its length. Once the enlarging means is placedwithin the sealing means the overall barrier means assembly takes on theprimary curvature of the enlarging means. This modularity allowsenlarging means with specific curvatures to be fabricated for defectsoccurring in various regions of the annulus.

The cross sectional shape of the barrier means 12 means can be any of anumber of shapes. Each embodiment exploits a sealing means 51 and anenlarging means 53 that may further add stiffness to the overall barrierconstruct. FIGS. 30A and 30B show an elongated cylindrical embodimentwith enlarging means 53 located about the long axis of the device. FIGS.31A and 31B depicts a barrier means comprising an enlarging means 53with a central cavity 49. FIGS. 32A and 32B depicts a barrier meanscomprising a non-axisymmetric sealing means 51. In use, the longersection of sealing means 51 as seen on the left side of this figurewould extend between opposing vertebra 50 and 50′. FIGS. 33A and 33Bdepict a barrier means comprising a non-axisymmetric sealing means 51and enlarging means 53. The concave portion of the barrier meanspreferably faces nucleus pulposus 20 while the convex surface faces thedefect 16 and the inner aspect of the annulus fibrosis 10. Thisembodiment exploits pressure within the disc to compress sealing means51 against neighboring vertebral bodies 50 and 50′ to aid in sealing.The ‘C’ shape as shown in FIG. 33A is the preferred shape of the barrierwherein the convex portion of the patch rests against the interioraspect of the AF while the concave portion faces the NP. To improved thesealing ability of such a patch, the upper and lower portions of this‘C’ shaped barrier means are positioned against the vertebral endplatesor overlying cartilage. As the pressure within the nucleus increases,these portions of the patch are pressurized against the endplates withan equivalent pressure, preventing the passage of materials around thebarrier means. Dissecting a matching cavity prior to or during patchplacement can facilitate use of such a ‘C’ shaped patch.

FIGS. 34 through 41 depict various enlarging or expansion device's 53that can be employed to aid in expanding a sealing element 51 within theintervertebral disc 15. Each embodiment can be covered by, coated with,or cover the sealing element 51. The sealing element 51 or membrane canbe a sealer which can prevent flow of a material within the annulusfibrosus of the intervertebral disk through a defect in the disk. Thematerial within the annulus can include a nucleus pulposus or aprosthetic augmentation device, such as a hydrogel. The sealing means 51can further be woven through the expansion means 53.

FIGS. 34 through 38 depict alternative patterns to that illustrated inFIG. 33A. FIG. 33A shows the expansion devices 53 within the sealingmeans 51. The sealing means can alternatively be secured to one oranother face (concave or convex) of the expansion means 53. This canhave advantages in reducing the overall volume of the barrier means 12,simplifying insertion through a small diameter cannula. It can alsoallow the barrier means 12 to induce ingrowth of tissue on one face andnot the other. The sealing means 51 can be formed from a material thatresists ingrowth such as expanded polytetraflouroethylene (e-PTFE). Theexpansion means can be constructed of a metal or polymer that encouragesingrowth. If the e-PTFE sealing means 51 is secured to the concave faceof the expansion means 53, tissue can grow into the expansion means 53from outside of the disc 15, helping to secure the barrier means 12 inplace and seal against egress of materials from within the disc 15.

The expansion means 53 shown in FIG. 33A can be inserted into thesealing means 51 once the sealing means 51 is within the disc 15.Alternatively, the expansion means 53 and sealing means 51 can beintegral components of the barrier means 12 that an be inserted as aunit into the disc.

The patterns shown in FIGS. 34 through 38 can preferably be formed froma relatively thin sheet of material. The material may be a polymer,metal, or gel, however, the superelastic properties of nickel titaniumalloy NITINOL makes this metal particularly advantageous in thisapplication. Sheet thickness of between 0.03″ to 0.10″ can provideadequate expansion force to maintain contact between the sealing means51 and surrounding vertebral endplates. The pattern may be wire EDM'ed,cut by laser, or formed by other suitable means.

FIG. 34 shows an embodiment of a non-axisymmetric or expander 53 havinga superior surface 166 and an inferior surface 168. The expander 53 canform a frame of a barrier 12. This embodiment comprises dissectingsurfaces or ends 160, radial elements or fingers 162 and a central strut164. The circular shape of the dissecting ends 160 aid in dissectingthrough the nucleus pulposus 20 and/or along an inner surface of theannulus fibrosis 10. The distance between the left-most and right-mostpoints on the dissecting ends is the expansion means length 170. Thislength 170 preferably lies along the inner perimeter of the posteriorannulus following implantation. The expander length 170 can be as shortas 3 mm and as long as the entire interior perimeter of the annulusfibrosis. The superior-inferior height of these dissecting ends 160 ispreferably similar to or larger than the posterior disc height.

This embodiment employs a multitude of fingers 162 to aid in holding aflexible sealer or membrane against the superior and inferior vertebralendplates. The distance between the superior-most point of the superiorfinger and the inferior-most point on the inferior finger is theexpansion means height 172. This height 172 is preferably greater thanthe disc height at the inner surface of the posterior annulus. Thegreater height 172 of the expander 153 allows the fingers 162 to deflectalong the superior and inferior vertebral endplates, enhancing the sealof the barrier means 12 against egress of material from within the disc15.

The spacing between the fingers 162 along the expander length 170 can betailored to provide a desired stiffness of the expansion means 153.Greater spacing between any two neighboring fingers 162 can further beemployed to insure that the fingers 170 do not touch if the expansionmeans 153 is required to take a bend along its length.

The central strut 164 can connect the fingers and dissecting ends andpreferably lies along the inner surface of the annulus 10 when seatedwithin the disc 15. Various embodiments may employ struts 164 of greateror lesser heights and thickness to vary the stiffness of the overallexpansion means 153 along its length 170 and height 172.

FIG. 35 depicts an alternative embodiment to the expander 153 of FIG.34. Openings or slots 174 can be included along the central strut 164.These slots 174 promote bending of the expander 153 and fingers 162along a central line 176 connecting the centers of the dissecting ends160. Such central flexibility has been found to aid against superior orinferior migration of the barrier means or barrier 12 when the barrier12 has not been secured to surrounding tissues.

FIG. 36 depicts an embodiment of the expander 153 of FIG. 33A with anenlarged central strut 164 and a plurality of slots 174. This centralstrut 164 can have a uniform stiffness against superior-inferior 166,168 bending as shown in this embodiment. The strut 164 can alternativelyhave a varying stiffness along its height 178 to either promote orresist bending at a given location along the inner surface of theannulus 10.

FIGS. 37A, B, and C depict a further embodiment of the frame or expander153. This embodiment employs a central lattice 180 consisting ofmultiple, fine interconnected struts 182. Such a lattice 180 can providea structure that minimizes bulging of the sealing means 51 underintradiscal pressures. The orientation and location of these struts 182have been designed to give the barrier 12 a bend-axis along the middleof the expander height 172. The struts 182 support inferior 168 andsuperior 166 fingers 162 similar to previous embodiments. However, thesefingers 162 can have varying dimensions and stiffness along the lengthof the barrier 12. Such fingers 162 cab be useful for helping the sealer51 conform to uneven endplate geometries. FIG. 37B illustrates thecurved cross section 184 of the expander 153 of FIG. 37A. This curve 184can be an arc segment of a circle as shown. Alternatively, the crosssection can be an ellipsoid segment or have a multitude of arc segmentsof different radii and centers. FIG. 37C is a perspective view showingthe three dimensional shape of the expander 153 of FIGS. 37A and 37B.

FIG. 38 depicts an expander 153 similar to that of FIG. 37A withoutfingers. The expander 153 includes a central lattice 180 consisting ofmultiple struts 182.

FIGS. 39 through 41 depict another embodiment of the expander 153 of thepresent invention. These tubular expanders can be used in the barrier 12embodiment depicted in FIG. 31A. The sealer 51 can cover the expander153 as shown in FIG. 31A. Alternatively, the sealer 51 can cover theinterior surface of the expander or an arc segment of the tube along itslength on either the interior or exterior surface.

FIG. 39 depicts an embodiment of a tubular expander 154. The superior166 and interior surfaces 168 of the tubular expander 154 can deployagainst the superior and inferior vertebral endplates, respectively. Thedistance 186 between the superior 166 and inferior 168 surfaces of theexpander 154 are preferably equal to or greater than the posterior discheight at the inner surface of the annulus 10. This embodiment has anannulus face 188 and nucleus face 190 as shown in FIGS. 39B, 39C and39D. The annulus face 188 can be covered by the sealer 51 from thesuperior 166 to inferior 168 surface of the expander 154. This face 188lies against the inner surface of the annulus 10 in its deployedposition and can prevent egress of materials from within the disc 15.The primary purpose of the nucleus face 190 is to prevent migration ofthe expander 154 within the disc 15. The struts 192 that form thenucleus face 190 can project anteriorly into the nucleus 20 when thebarrier 12 is positioned across the posterior wall of the annulus 10.This anterior projection can resist rotation of the tubular expansionmeans 154 about its long axis. By interacting with the nucleus 20, thestruts 192 can further prevent migration around the circumference of thedisc 15.

The struts 192 can be spaced to provide nuclear gaps 194. These gaps 194can encourage the flow of nucleus pulposus 20 into the interior of theexpander 154. This flow can insure full expansion of the barrier 12within the disc 15 during deployment.

The embodiments of FIGS. 39, 40 and 41 vary by their cross sectionalshape. FIG. 39 has a circular cross section 196 as seen in FIG. 39C. Ifthe superior-inferior height 186 of the expander 154 is greater thanthat of the disc 15, this circular cross section 196 can deform into anoval when deployed, as the endplates of the vertebrae compress theexpander 154. The embodiment of the expander 154 shown in FIG. 40 ispreformed into an oval shape 198 shown in FIG. 40C. Compression by theendplates can exaggerate the unstrained oval 198. This oval 198 canprovide greater stability against rotation about a long axis of theexpander 154. The embodiment of FIGS. 41B, 41C and 41D depict an‘egg-shaped’ cross section 202, as shown in FIG. 41C, that can allowcongruity between the curvature of the expander 154 and the inner wallof posterior annulus 10. Any of a variety of alternate cross sectionalshapes can be employed to obtain a desired fit or expansion forcewithout deviating from the spirit of the present invention.

FIGS. 40E, 40F and 401 depict the expander 154 of FIGS. 40A, 40B, 40C,and 40D having a sealing means 51 covering the exterior surface of theannulus face 188. This sealing means 51 can be held against theendplates and the inner surface of the posterior annulus by the expander154 in its deployed state.

FIGS. 40G and 40H depict the expander 154 of FIG. 40B with a sealer 51covering the interior surface of the annulus face 188. This position ofthe sealer 51 can allow the expander 154 to contact both the vertebralendplates and inner surface of the posterior annulus. This can promoteingrowth of tissue into the expander 154 from outside the disc 15.Combinations of sealer 51 that cover all or part of the expander 154 canalso be employed without deviating from the scope of the presentinvention. The expander 154 can also have a small pore size therebyallowing retention of a material such as a nucleus pulposus, forexample, without the need for a sealer as a covering.

FIGS. 42A-D depicts cross sections of a preferred embodiment of sealingmeans 51 and enlarging means 53. Sealing device 51 has internal cavity17 and opening 8 leading from its outer surface into internal cavity 17.Enlarger 53 can be inserted through opening 8 and into internal cavity17.

FIGS. 43A and 43B depict an alternative configuration of enlarger 53.Fixation region 4 extends through opening 8 in sealing means 51.Fixation region 4 has a through-hole that can facilitate fixation ofenlarger 53 to tissues surrounding defect 16.

FIGS. 44A and 44B depict an alternative shape of the barrier. In thisembodiment either sealing device 51, enlarger 53, or both have acurvature with radius R. This curvature can be used in any embodiment ofthe present invention and may aid in conforming to the curved innercircumference of annulus fibrosis 10.

FIG. 45 is a section of a device used to affix sealing means 51 totissues surrounding a defect. In this figure, sealing means 51 would bepositioned across interior aspect 50 of defect 16. The distal end ofdevice 110′ would be inserted through defect 16 and opening 8 into theinterior cavity 17. On the right side of this figure, fixation dart 25has been passed from device 110′, through a wall of sealing means 51 andinto tissues surrounding sealing means 51. On the right side of thefigure, fixation dart 25 is about to be passed through a wall of sealingmeans 51 by advancing pusher 111 relative to device 110′ in thedirection of the arrow.

FIG. 46 depicts the use of thermal device 200 to heat sealing means 51and adhere it to tissues surrounding a defect. In this figure, sealingmeans 51 would be positioned across the interior aspect 36 of a defect16. The distal end of thermal device 200 would be inserted through thedefect and opening 8 into interior cavity 17. In this embodiment,thermal device 200 employs at its distal end resistive heating element210 connected to a voltage source by wires 220. Covering 230 is anon-stick surface such as Teflon tubing that ensures the ability toremove device 200 from interior cavity 17. In this embodiment, device200 would be used to heat first one half, and then the other half ofsealing means 51.

FIG. 47 depicts an expandable thermal element, such as a balloon, thatcan be used to adhere sealing means 51 to tissues surrounding a defect.Sealing means 51 is not shown. As in FIG. 18, the distal end of device130 would be inserted through the defect and opening 8 into interiorcavity 17, with balloon 150′ on the distal end device 130 in a collapsedstate. Balloon 150′ is then inflated to expanded state 150, expandingsealing means 51. Expanded balloon 150 could heat sealing means 51 andsurrounding tissues by inflating it with a heated fluid or by employingRF electrodes. In this embodiment, device 130 would be used to expandand heat first one half, then the other half of sealing means 51.

FIG. 48 depicts an alternative embodiment to device 130. This deviceemploys an elongated, flexible balloon 150′ that can be inserted intoand completely fill internal cavity 17 of sealing means 51 prior toinflation to an expanded state 150. Using this embodiment, inflation andheating of sealing means 51 can be performed in one step.

FIGS. 49A through 49G illustrate a method of implanting an intradiscalimplant. An intradiscal implant system consists of an intradiscalimplant 400, a delivery device or cannula 402, an advancer 404 and atleast one control filament 406. The intradiscal implant 400 is loadedinto the delivery cannula 402 which has a proximal end 408 and a distalend 410. FIG. 49A illustrates the distal end 410 advanced into the disc15 through an annulotomy 416. This annulotomy 416 can be through anyportion of the annulus 20, but is preferably at a site proximate to adesired, final implant location. The implant 400 is then pushed into thedisc 15 through the distal end 410 of the cannula 402 in a directionthat is generally away from the desired, final implant location as shownin FIG. 49B. Once the implant 400 is completely outside of the deliverycannula 402 and within the disc 15, the implant 400 can be pulled intothe desired implant location by pulling on the control filament 406 asshown in FIG. 49C. The control filament 406 can be secured to theimplant 400 at any location on or within the implant 400, but ispreferably secured at least at a site 414 or sites on a distal portion412 of the implant 400, i.e. that portion that first exits the deliverycannula 402 when advanced into the disc 15. These site 414 or sites aregenerally furthest from the desired, final implant location once theimplant has been fully expelled from the interior of the deliverycannula 402.

Pulling on the control filament 406 causes the implant 400 to movetoward the annulotomy 416. The distal end 410 of the delivery cannula402 can be used to direct the proximal end 420 of the implant 400 (thatportion of the implant 400 that is last to be expelled from the deliverycannula 402) away from the annulotomy 416 and toward an inner aspect ofthe annulus 20 nearest the desired implant location. Alternately, theadvancer 404 can be used to position the proximal end of the implanttoward an inner aspect of the annulus 20 near the implant location, asshown in FIG. 49E. Further pulling on the control filament 406 causesthe proximal end 426 of the implant 400 to dissect along the inneraspect of the annulus 20 until the attachment site 414 or sites of theguide filament 406 to the implant 400 has been pulled to the inneraspect of the annulotomy 416, as shown in FIG. 49D. In this way, theimplant 400 will extend at least from the annulotomy 416 and along theinner aspect of the annulus 20 in the desired implant location,illustrated in FIG. 49F.

The implant 400 can be any of the following: nucleus replacement device,nucleus augmentation device, annulus augmentation device, annulusreplacement device, the barrier of the present invention or any of itscomponents, drug carrier device, carrier device seeded with livingcells, or a device that stimulates or supports fusion of the surroundingvertebra. The barrier or implant 400 can be a membrane which preventsthe flow of a material from within the annulus fibrosus of anintervertebral disk through a defect in the disk. The material withinthe annulus fibrosus can be, for example, a nucleus pulposus or aprosthethic augmentation device, such as hydrogel. The membrane can be asealer. The implant 400 can be wholly or partially rigid or wholly orpartially flexible. It can have a solid portion or portions that containa fluid material. It can comprise a single or multitude of materials.These materials can include metals, polymers, gels and can be in solidor woven form. The implant 400 can either resist or promote tissueingrowth, whether fibrous or bony.

The cannula 402 can be any standard tubular device capable of advancingthe implant 400 at least partially through the annulus 20. It can bemade of any suitable biocompatible material including various knownmetals and polymers. It can be wholly or partially rigid or flexible. Itcan be circular, oval, or polygonal in cross section. It must have anopening at least at its distal end 410, but can have other openings invarious locations along its length.

The advancer 404 can be rigid or flexible, and have one of a variety ofcross sectional shapes either like or unlike the delivery cannula 402.It may be a solid or even a column of incompressible fluid so long as itis stiff enough to advance the implant 400 into the disc 15. Theadvancer 404 can be contained entirely within the cannula 402 or canextend through a wall or end of the cannula to facilitate manipulation.

Advancement of the implant 400 can be assisted by various levers, gears,screws and other secondary assist devices to minimize the force requiredby the surgeon to advance the implant 400. These secondary devices canfurther give the user greater control over the rate and extent ofadvancement into the disc 15.

The guide filament 406 may be a string, rod, plate, or other elongateobject that can be secured to and move with the implant 400 as it isadvanced into the disc 15. It can be constructed from any of a varietyof metals or polymers or combination thereof and can be flexible orrigid along all or part of its length. It can be secured to a secondaryobject 418 or device at its end opposite that which is secured to theimplant 400. This secondary device 418 can include the advancer 404 orother object or device that assists the user in manipulating thefilament. The filament 406 can be releasably secured to the implant 400,as shown in FIG. 49G or permanently affixed. The filament 406 can belooped around or through the implant. Such a loop can either be cut orhave one end pulled until the other end of the loop releases the implant400. It may be bonded to the implant 400 using adhesive, welding, or asecondary securing means such as a screw, staple, dart, etc. Thefilament 406 can further be an elongate extension of the implantmaterial itself. If not removed following placement of the implant, thefilament 406 can be used to secure the implant 400 to surroundingtissues such as the neighboring annulus 20, vertebral endplates, orvertebral bodies either directly or through the use of a dart, screw,staple, or other suitable anchor.

Multiple guide filaments can be secured to the implant 400 at variouslocations. In one preferred embodiment, a first or distal 422 and asecond or proximal 424 guide filament are secured to an elongate implant400 at or near its distal 412 and proximal 420 ends at attachment sites426, 428, respectively. These ends 412, 420 correspond to the first andlast portions of the implant 400, respectively, to be expelled from thedelivery cannula 402 when advanced into the disc 15. This double guidefilament system allows the implant 400 to be positioned in the samemanner described above in the single filament technique, and illustratedin FIG. 50A through FIG. 50C. However, following completion of thisfirst technique, the user may advance the proximal end 420 of the device400 across the annulotomy 416 by pulling on the second guide filament424, shown in FIG. 50D. This allows the user to controllably cover theannulotomy 416. This has numerous advantages in various implantationprocedures. This step may reduce the risk of herniation of eithernucleus pulposus or the implant itself. It may aid in sealing the disc,preserving disc pressure and the natural function of the disc. It mayencourage ingrowth of fibrous tissue from outside the disc into theimplant. It may further allow the distal end of the implant to restagainst annulus further from the defect created by the annulotomy.Finally, this technique allows both ends of an elongate implant to besecured to the disc or vertebral tissues.

Both the first 422 and second 424 guide filaments can be simultaneouslytensioned, as shown in FIG. 50E, to ensure proper positioning of theimplant 400 within the annulus 20. Once the implant 400 is placed acrossthe annulotomy, the first 422 and second 424 guide filaments can beremoved from the input 400, as shown in FIG. 50F. Additional controlfilaments and securing sites may further assist implantation and/orfixation of the intradiscal implants.

In another embodiment of the present invention, as illustrated in FIGS.51A through 51C, an implant guide 430 may be employed to aid directingthe implant 400 through the annulotomy 416, through the nucleus pulposus10, and/or along the inner aspect of the annulus 20. This implant guide430 can aid in the procedure by dissecting through tissue, addingstiffness to the implant construct, reducing trauma to the annulus orother tissues that can be caused by a stiff or abrasive implant,providing 3-D control of the implants orientation during implantation,expanding an expandable implant, or temporarily imparting a shape to theimplant that is beneficial during implantation. The barrier guide 430can be affixed to either the advancer 404 or the implant 406 itself.

In a preferred embodiment shown in FIGS. 52A and 52B, the implant guide430 is secured to the implant 400 by the first 424 and second 426 guidefilaments of the first 426 and the second 428 attachment sites,respectively. The guide filaments 424, 426 may pass through or aroundthe implant guide 430. In this embodiment, the implant guide 430 may bea thin, flat sheet of biocompatible metal with holes passing through itssurface proximate the site or sites 426, 428 at which the guidefilaments 422, 424 are secured to the implant 400. These holes allowpassage of the securing filament 422, 424 through the implant guide 430.Such an elongated sheet may run along the implant 400 and extend beyondits distal end 412. The distal end of the implant guide 430 may beshaped to help dissect through the nucleus 10 and deflect off of theannulus 20 as the implant 400 is advanced into the disc 15. When usedwith multiple guide filaments, such an implant guide 430 can be used tocontrol rotational stability of the implant 400. It may also be used toretract the implant 400 from the disc 15 should this become necessary.The implant guide 430 may also extend beyond the proximal tip 420 of theimplant 400 to aid in dissecting across the annulus 20 proximate thedesired implantation site.

The implant guide 430 is releasable from the implant 400 following orduring implantation. This release may be coordinated with the release ofthe guide filaments 422, 424. The implant guide 430 may further be ableto slide along the guide filaments 422, 424 while these filaments aresecured to the implant 400.

Various embodiments of the barrier 12 or implant 400 can be secured totissues within the intervertebral disc 15 or surrounding vertebrae. Itcan be advantageous to secure the barrier means 12 in a limited numberof sites while still insuring that larger surfaces of the barrier 12 orimplant juxtapose the tissue to which the barrier 12 is secured. This isparticularly advantageous in forming a sealing engagement withsurrounding tissues.

FIGS. 53-57 illustrate barriers having stiffening elements 300. Thebarrier 12 can incorporate stiffening elements 300 that run along alength of the implant required to be in sealing engagement. Thesestiffening elements 300 can be one of a variety of shapes including, butnot limited to, plates 302, rods 304, or coils. These elements arepreferably stiffer than the surrounding barrier 12 and can impart theirstiffness to the surrounding barrier. These stiffening elements 300 canbe located within an interior cavity formed by the barrier. They canfurther be imbedded in or secured to the sealing element.

Each stiffening element can aid in securing segments of the barrier 12to surrounding tissues. The stiffening elements can have parts 307,including through holes, notches, or other indentations for example, tofacilitate fixation of the stiffening element 300 to surrounding tissuesby any of a variety of fixation devices 306. These fixation devices 306can include screws, darts, dowels, or other suitable means capable ofholding the barrier 12 to a surrounding tissue. The fixation devices 306can be connected either directly to the stiffening element 300 orindirectly using an intervening length of suture, cable, or otherfilament for example. The fixation device 306 can further be secured tothe barrier 12 near the stiffening element 300 without direct contactwith the stiffening element 300.

The fixation device 306 can be secured to or near the stiffening element300 at opposing ends of the length of the barrier 12 required to be insealing engagement with surrounding tissues. Alternatively, one or amultitude of fixation devices 306 can be secured to or near thestiffening element 300 at a readily accessible location that may not beat these ends. In any barrier 12 embodiment with an interior cavity 17and an opening 8 leading thereto, the fixation sites may be proximal tothe opening 8 to allow passage of the fixation device 306 and variousinstruments that my be required for their implantation.

FIGS. 53A and 53B illustrate one embodiment of a barrier 12incorporating the use of a stiffening element 300. The barrier 12 can bea plate and screw barrier 320. In this embodiment, the stiffeningelements 300 consists of two fixation plates, superior 310 and inferior312, an example of which is illustrated in FIGS. 54A and 54B with twoparts 308 passing through each plate. The parts 308 are located proximalto an opening 8 leading into an interior cavity 17 of the barrier 12.These parts 8 allow passage of a fixation device 306 such as a bonescrew. These screws can be used to secure the barrier means 12 to asuperior 50 and inferior 50′ vertebra. As the screws are tightenedagainst the vertebral endplate, the fixation plates 310, 312 compressthe intervening sealing means against the endplate along the superiorand inferior surfaces of the barrier 12. This can aid in creating asealing engagement with the vertebral endplates and prevent egress ofmaterials from within the disc 15. As illustrated in FIGS. 53A and 53B,only the superior screws have been placed in the superior plate 310,creating a sealing engagement with the superior vertebra.

FIGS. 55A and 55B illustrate another embodiment of a barrier 12 havingstiffening elements 300. The barrier 12 can be an anchor and rod barrier322. In this embodiment, the stiffening elements 300 consist of twofixation rods 304, an example of which is shown in FIGS. 56A and 56B,imbedded within the barrier 12. The rods 304 can include a superior rod314 and an inferior rod 316. Sutures 318 can be passed around these rods314 and 316 and through the barrier means 10. These sutures 318 can inturn, be secured to a bone anchor or other suitable fixation device 306to draw the barrier 12 into sealing engagement with the superior andinferior vertebral endplates in a manner similar to that describedabove. The opening 8 and interior cavity 17 of the barrier 12 are notrequired elements of the barrier 12.

FIG. 57 illustrates the anchor and rod barrier 322, described above,with fixation devices 306 placed at opposing ends of each fixation rod316, 318. The suture 18 on the left side of the superior rod 318 has yetto be tied.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

What is claimed is:
 1. An implant for implantation between a nucleus andan anulus and across a defect in the anulus in an intervertebral disc,comprising: a barrier having a first and second surface, wherein saidfirst surface is adapted to present a concave surface facing the nucleusin the implanted orientation and wherein said barrier is dimensioned toextend along the anulus across and beyond the periphery of the areadefining a defeat.
 2. The implant of claim 1, wherein said barrier isresilient.
 3. The implant of claim 1, wherein said barrier is adapted tocontact load bearing anulus tissue sufficient to prevent extrusion ofsaid barrier through said defect.
 4. The implant of claim 1, whereinsaid barrier is adapted to contact load bearing vertebral body endplatetissue sufficient to prevent extrusion of said barrier through saiddefect.
 5. The implant of claim 1, wherein said barrier has a width ofat least 1 cm.
 6. The implant of claim 1, wherein said barrier has aheight of at least 0.05 cm.
 7. The implant of claim 1, wherein saidsecond surface is adapted to present a convex surface in conformity withthe interior surface of the anulus.
 8. The implant of claim 1, whereinsaid second surface is adapted to present a convex surface in conformitywith the endplates.
 9. The implant of claim 1, wherein said barrier isadapted to fit between the nucleus and the anulus.
 10. The implant ofclaim 1, wherein said barrier has a top and bottom edge and a first andsecond side edge, wherein said top and bottom edge are dimensioned tocontact the endplates at maximum distraction.
 11. The implant of claim1, wherein said barrier is dimensioned such that when the barrier iscentered in the posterior anulus, the first and second side edges ofsaid barrier lie beyond the posterior anulus and along opposite lateralwalls of the anulus.
 12. A device for augmenting an anulus of anintervertebral disc suitable for inserting along an interior aspect ofan anular lamella substantially in front of a defect in the anulus,comprising: a thin resilient barrier having a first surface facing aninterior aspect of the anular lamella and a second surface facing theinterior of the intervertebral disc, wherein said barrier is adapted tobe sealably positioned against the lamella via the exertion of force onthe second surface sustained by a pressurized intervertebral discenvironment.
 13. The device of claim 12, wherein the barrier is adaptedto be inserted between the anulus and the nucleus.
 14. A device forpartially encapsulating inter-anular material comprising resilientflexible material adapted to conform to at least a portion of theinterior surface of an anulus fibrosus and of sufficient size andsufficient rigidity to not be extrudable through an anulus defect. 15.An anulus augmentation implant for insertion along the surface of ananular lamella and across a defect in an intervertebral disc,comprising: a collapseable resilient barrier having a top and bottomedge and a first and second side edge, wherein the top and bottom edgeare sized to contact the endplates at maximum distraction; and whereinthe first and second edge extend beyond the defect.
 16. The device ofclaim 15, wherein the barrier has a concave cross section along at leasta portion of its length.
 17. The implant of claim 15, wherein the firstedge and the second edge are adapted to extend beyond the posterioranulus when implanted.
 18. A device for transferring intervertebral discpressure from a defect in an anulus fibrosus to load bearing tissue,comprising: a flexible barrier having a first convex surface and asecond concave surface; wherein the first convex surface is incommunication with a portion of the posterior anulus; wherein the secondconcave surface is in communication with the nucleus pulposus; andwherein said barrier is dimensioned to extend beyond the periphery ofthe area defining the defect such that the barrier contacts load bearingintervertebral disc tissue.
 19. A dynamically stable device forshielding defects in an anulus fibrosus of an intervertebral disc,comprising: a flexible membrane adapted to yield to interdiscal pressureand conform to at least a portion of the posterior anulus under bothdistraction and compression of the disc, wherein said membrane is sizedto extend along the interior of The posterior anulus.
 20. The device ofclaim 19, wherein the device has a width in a lateral direction and aheight in an inferior-superior direction, wherein the height exceeds thedistance between an inferior vertebral body and a superior vertebralbody when filly distracted so that the device is concave inwardly alongan inferior superior axis in the implanted orientation.